Disk drives comprise a disk and a head connected to a distal end of an actuator arm which is rotated about a pivot by a voice coil motor (VCM) to position the head radially over the disk. The disk comprises a plurality of radially spaced, concentric tracks for recording user data sectors and servo sectors. The servo sectors comprise head positioning information (e.g., a track address) which is read by the head and processed by a servo control system to control the velocity of the actuator arm as it seeks from track to track.
The control circuitry of the disk drive typically comprises various components, such as a read channel or a preamp which may be developed by vendors that supply disk drive manufacturers. The preamp generates the write signal applied to the head during write operations, and amplifies the read signal generated by the head during read operations. The read channel performs suitable encoding of the data written to the disk, and demodulates the read signal into an estimated data sequence representing the data recorded on the disk. The read channel may also perform various functions associated with the servo system for servoing the head over the disk, such as servo sector processing.
A problem arises when a disk drive manufacturer engages a new component vendor, such as a read channel vendor or preamp vendor. The new vendor typically needs to evaluate how the current vendors implement the code segments for interfacing with the disk drive in order to understand and implement interoperability with the disk drive. However, the code segments for implementing the component interface may include proprietary information owned by the current vendors and therefore cannot be disclosed to a new vendor.